CO2 photocatalytic reduction is a carbon–neutral renewable energy technology. However, this technology is restricted by the low utilization of photocatalytic electrons. Therefore, to improve the separation efficiency of photogenerated carriers and enhance the performance of CO2 photocatalytic reduction. In this paper, g-C3N4/Pd composite with Schottky junction was synthesized by using g-C3N4, a two-dimensional material with unique interfacial effect, as the substrate material in combination with the co-catalyst Pd. The composite of Pd and g-C3N4 was tested to have a strong localized surface plasmon resonance effect (LSPR), which decreased the reaction barriers and improved the electron utilization. The combination of reduced graphene oxide (rGO) created a π–π conjugation effect at the g-C3N4 interface, which shortened the electron migration path and further improved the thermal electron transfer and utilization efficiency. The results show that the g-C3N4/ rGO/Pd (CRP) exhibits the best performance for photocatalytic reduction of CO2, with the yields of 13.57 μmol g− 1 and 2.73 μmol g− 1 for CO and CH4, respectively. Using the in situ infrared test to elucidate the intermediates and the mechanism of g-C3N4/rGO/Pd (CRP) photocatalytic CO2 reduction. This paper provides a new insight into the interface design of photocatalytic materials and the application of co-catalysts.

Interface engineering enhanced g-C3N4rGOPd composites synergetic localized surface plasmon resonance effect for boosting photocatalytic CO2 reduction
    Abstract
        Graphical abstract
    1 Introduction
    2 Experiment
        2.1 Preparation of 2D g-C3N4
        2.2 Preparation of Pd nanosheets and Pd nano-cubes
        2.3 Preparation of 2D g-C3N4Pd
        2.4 Preparation of 2D g-C3N4rGOPd
        2.5 Photocatalytic performance test for CO2 reduction
    3 Results and discussion
        3.1 Photocatalyst characterization
        3.2 Photoelectric characteristics analysis
        3.3 Performance test
        3.4 Mechanism of photocatalytic CO2 reduction
    4 Conclusion
    Acknowledgements 
    References

• Yang Wan(Institute of Green Chemistry and Chemical Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China)
• Qi Liu(Institute of Green Chemistry and Chemical Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China)
• Zenghui Xu(China Construction Eco-Environmental Protection Technology CO., LTD., Suzhou 215124, People’s Republic of China)
• Jinze Li(China Construction Eco-Environmental Protection Technology CO., LTD., Suzhou 215124, People’s Republic of China)
• Huijie Wang(Institute of Green Chemistry and Chemical Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China)
• Mengyang Xu(Institute of Green Chemistry and Chemical Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China)
• Chenlong Yan(School of Energy and Power Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China)
• Xianghai Song(Institute of Green Chemistry and Chemical Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China)
• Xin Liu(Institute of Green Chemistry and Chemical Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China)
• Huiqin Wang(School of Energy and Power Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China)
• Weiqiang Zhou(Institute of Green Chemistry and Chemical Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China)
• Pengwei Huo(Institute of Green Chemistry and Chemical Technology, School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China)